Hey guys, I've got a slight issue with my early 99 7.3. I've noticed that when driving and accelerating normally, a slight knocking sound will develop. It starts around 1900 rpms and goes away around 2150ish rpms. Other than that, the truck runs fine. No smoke at idle or anything. Another thing I have noticed is the truck is running abnormally cold. For instance, today I pulled a fully loaded peanut trailer which weighs about 10,000 pounds. I never got above 30mph with it, and only went about 8 or 9 miles from the field back to the farm. However, I had been driving quite a bit before this and the truck still never got to where it used to run for temperature. It was also about 55 degrees out when I pulled the trailer, and before that in the afternoon, it was about 70. Could the colder running of the truck be what's causing the knock? I'm kind of at a loss on this one. Thanks for any help.

 

Regarding running cold sounds like your thermostat took a crap. Mine did that same thing last winter, new thermostat truck ran at normal operating temperature. I replaced both hoses and bought a billet thermostat housing too.

 

Yeah I was thinking that a new thermostat would most likely solve the cold running issue, I'm really curious if the knocking noise is related to the cold running.

 

Do an injector buzz test and see how they sound. Could be an injector knocking or going bad and causing cold running issues.

 

Mine does not knock when I run it before it's warmed up.

 

A buzz test will definitely be on the to-do list. I've also been researching the 203* thermostat compared to the stock 195* thermostat. After reading quite a bit, I'm leaning towards the 203* thermostat. Any reason I should stay away from it? Also, walleye hunter, where did you purchase your bellowed up-pipes from? I'm seeing a little soot start to build up on mine, but I can't find the bellowed pipes for an early 99 anywhere except riffraff diesel. The problem is that they have them listed for $800 which isn't something I can justify for up-pipes.

 

I got them from Riffraff but there is more to the story. I also upgraded to the later turbo, pedestal and plenums. I had the parts from a truck I parted out and wasn't sure that I wanted to do it but the cheaper price for the up pipes sealed the deal for me.

 

Oops my bad. I was selective reading your signature and didn't notice the "99.5+ plenums". Guess its back to craigslist looking for a 99.5+ parts truck lol.

 

You were looking at the International E99 up pipes, here's the link for the E99 from RR, $459!
Riffraff Diesel Bellowed Up-pipe Kit for Ford 7.3L 94-Early 99

 

Here's my source, there are a lot of vehicles with the 7.3 in them. I concentrate on light and heavy trucks, vans, school buses and ambulances. There were a lot of E-450 buses sold out of DC. Enter a location search and have at it.

https://www.govdeals.com/index.cfm

 

Apparently I wasn't looking very hard when I first checked RiffRaff. Thanks for the link

 

Well that site sure puts Craigslist to shame . I will definitely searching on here quite often. Thanks for the link

 

Don't get addicted to it!